I am using Octave (3.6) on Ubuntu 10.0.4 LTS. I want to do some research involving symbolic math. I was thinking of downloading sage (I just found about it today) - but thought I'd better ask in here - at least, I'm already familiar with Octave.
Sage uses many symbolic computation packages: Maxima, Singular, etc. For each functionality, it picks the most suitable algorithm from all the packages. It also allows direct interface to all packages.
FWIW, Sage also connects to Octave. Consult: reference/sage/interfaces/octave.
MATLAB has a symbolic toolbox where it allows defining symbolic variables via